1. Field of the Invention
The present invention relates to a foot pedal locking device for a cargo-handling vehicle such as shovel loaders and fork-lift trucks.
2. Description of the Related Art
In conventional cargo-handling vehicles such as a four-wheel drive small-type shovel loader, an operator is likely to accidentally step on a foot pedal when getting into or out of an operator compartment at an entrance located at the front of the vehicle. If a lift-arm operating pedal is accidentally depressed, the lift arm of the shovel loader is lowered. Similarly, if a vehicle drive pedal is depressed, the vehicle starts to move. In order to prevent such accidents, a locking device for preventing a foot pedal from rotating, i.e. pivoting, has been disclosed in U.S. Pat. No. 4,397,371.
In this locking device, a lock member is spring-loaded to be able to move up and down. Usually, the lock member is held in an up position by the spring. At the lower end of the lock member is fixedly attached a control link, for preventing the operation of a fluid control device and the rotation of the foot pedal. In this case, there is provided a seat bar (a restraining means) which, when turned to an operator restraining position, pushes the aforesaid lock member against the force of the spring, thus moving the lock member down. In this state, as the control link is swingable, both the fluid control device and the foot pedal also become operable.
However, the lock member is moved upward by a spring force to fix the control link for the purpose of locking the fluid control device and the foot pedal; if the spring force is too weak to raise the lock member, the lock member cannot be moved upward to fix the control link. Therefore, increasing the spring force may be considered; if, however, the spring force is increased, the seat bar will require a greater force to move the lock member downward, possibly degrading unlocking quality.
Also, if the spring, the lock member and the control link get rusty, or if there is present a pebble or sand in the fixing part where the control link is secured to the lock member, the lock member is difficult to be smoothly moved, with the result that the fixing of the control link, the locking of the operation of the fluid control device and the locking of the foot pedal will become unreliable.
Other similar prior art techniques have also been proposed in U.S. Pat. Nos. 4,388,980 and 4,391,344.